Method for bleaching tackifying resins

ABSTRACT

A method for bleaching hydrocarbon tackifier resins which comprises adding a bleaching agent to a molten resin and recovering a bleached hydrocarbon tackifier resin. The bleaching agent comprises from about 0.04 wt. % to about 0.06 wt. %, based on the weight of the reaction mixture, of an iodine supplying compound and from about 2.0 wt. % to about 10.0 wt. %, based on the weight of the reaction mixture, of an activating terpene compound. The iodine supplying compound is selected from the group consisting of elemental iodine and hydrogen iodide. The activating compound is selected from the group consisting of α-terpinene, γ-terpinene, d-limonene, 1,4-cyclohexadiene and abietic acid.

This is a division of Ser. No. 07/702,253, filed May 17, 1991.

The present invention relates to methods for bleaching hydrocarbontackifier resins.

Tackifier resins are used as additives to elastomers for the formationof, among other things, hot melt adhesives. The color of tackifierresins added to the elastomer, to a large extent, determines the finalcolor of the adhesive. Therefore, it is desirable to produce resins withas little color as possible.

Hydrocarbon tackifier resins prepared by the cationic polymerization ofC₅ to C₁₀ unsaturated hydrocarbon monomers (e.g., terpenes, piperylene,2-methyl-2-butene, isoprene, styrene, α-methylstyrene, and the like)have undesirable dark colors. It is desirable to produce resins having alower level of color. It is known to use catalytic hydrogenation as ameans of decolorizing or bleaching hydrocarbon tackifier resins, but itsuse is expensive when compared to the use of iodine, which may be usedto bleach certain tackifying resins. It is also known that light coloredresins prepared from a substantial concentration of terpene monomers maybe bleached by treating the monomer feed or the dissolved resin withiodine, chlorine or bromine. See, for example, U.S. Pat. No. 4,482,688to Schluenz.

However, the use of iodine alone as a bleaching agent is only minimallyeffective for dark colored polymers prepared from non-terpenic C₅ to C₁₀unsaturated hydrocarbon monomers or polymers prepared from mixtures ofnon-terpenic and terpenic C₅ to C₁₀ unsaturated hydrocarbon monomerssince the process does not reduce the color to a maximum degree. Forexample, see Schluenz, Supra, Table I, Examples 3i-3l, where apiperylene based polymer is bleached from a color of 3 to a color of 2and a piperylene/vinyl cyclohexane based copolymer is bleached from acolor of 4- to a color of 3. In addition, iodine bleaching tends toproduce an undesirable green tint in the bleached resin. Therefore,there is a need for a method of bleaching hydrocarbon resins that ismore cost effective than catalytic hydrogenation and more effective thanthe use of iodine alone.

Accordingly, it is an object of the present invention to provide anefficient and cost effective method for bleaching hydrocarbon tackifyingresins of the class described such that they are substantially free ofcolor.

By the present invention, the bleaching of hydrocarbon tackifying resinsprepared by the cationic polymerization of C₅ to C₁₀ unsaturatedhydrocarbon monomers of the class described is conveniently conducted bybringing the resin to a molten state and then treating the molten resinwith a bleaching agent (comprising an iodine supplying compound and anactivating compound) for about an hour while retaining the resin in itsmolten state. A vacuum is then applied to the resin to remove thereaction product of the activating compound and substantially all of theiodine. The resin is then cooled for use as a tackifier. The resultingresin is substantially lighter in color (by about two to three Gardnernumbers) than the starting resin. In addition, there is no undesirablegreen cast to the bleached resin. An adhesive prepared by compounding aresin bleached according to the present invention with an elastomer hasadhesive properties substantially the same as an adhesive prepared withan untreated resin.

Previous processes, such as Schluenz, were effective at bleachingcertain resins during polymerization or prior to the removal of thesolvent. Attempts to bleach a resin in the molten state were effectiveonly with those resins which were compounded from between 100% and 75%terpene monomers and which were light in color, less than about 3+ onthe Gardner scale, prior to bleaching. In contrast, the presentinvention bleaches resins which are compounded from monomers other thanterpenes as well as resins which are copolymers of terpenes and otherhydrocarbons (such as, piperylene or styrene). In addition, thebleaching of these darker resins is accomplished conveniently in themolten state of the final resin.

Although the exact mechanism by which the combination of the iodinesupplying compound and the activating hydrogen donating compoundbleaches the resins is unknown, it is believed that the activatingcompound should preferably be one that will react with the iodinesupplying compound to donate labile (i.e., reactive) hydrogen to theresin. It is postulated that the process can be visualized as a hydrogenexchange or disproportionation between the activating compound and theresin. The reaction products of the activating compound (after resinbleaching) tend to show additional unsaturation which would indicatehydrogen donation to the resin. It is further believed that the iodinesupplying compound acts as a catalyst since there is no indication of anincrease in halogen content of the resin after bleaching.

One method of carrying out the invention involves bringing the resin toa temperature of between about 150° C. and about 260° C. and preferablybetween about 200° C. and about 240° C. At this point, between about 2.0wt % and about 10.0 wt. %, based on the weight of the reaction mixture,of the bleaching agent, comprising an iodine supplying compound and anactivating compound, is added to the molten resin. After between aboutfifteen minutes and an hour, a bleached resin is recovered that issuitable for use as a tackifier in adhesives that are substantially freeof unwanted color.

In the practice of the invention, the bleaching agent comprises aniodine supplying compound and an activating hydrogen donating compound,with the activating compound present at a molar concentration from about25 to about 200 times the molar concentration of the iodine supplyingcompound. The iodine supplying and activating compounds are added to themolten resin separately or are mixed and added together to the moltenresin.

It has been found that a preferred iodine supplying compound is selectedfrom the group consisting of elemental iodine and hydrogen iodide. Aspointed out, it is believed that the iodine supplying compound acts as acatalyst during the bleaching of the resin since there is no measurableincrease in the halogen content of the resin after bleaching. Bothiodine and the spent activating agent are removed together during vacuumstripping.

In general, any of a series of compounds with reactive hydrogensadjacent to one or more double bonds will act as an appropriateactivating hydrogen donating compound but α-terpinene, γ-terpinene,d-limonene, 1,4-cyclohexadiene and abietic acid are preferred activatingcompounds. The reaction products of the activating compounds show agreater amount of unsaturation than is shown in the starting material.For example, when a molten hydrocarbon tackifier resin is treated withiodine and d-limonene (with two sites of unsaturation), the reactionproduct of the activating compound is the aromatic compound, para-cymene(with three sites of unsaturation). The activating compounds and theirreaction products are removed from the resin by vacuum distillation.

Upon removal of the activating species, the bleached resin is cooled andmixed with an appropriate copolymeric elastomer, such as KRATON D-1107(Shell Chemical Co.) or ELVAX 250 (DuPont) with or without an oil, toproduce a formulated adhesive. The adhesive properties of the resultingformulated adhesive are comparable to the properties of an adhesiveprepared from an untreated resin, but the color of the adhesive preparedfrom the treated resin is usually at least two Gardner numbers lighterthan the color of an adhesive using an untreated resin.

Thus, the present invention provides an efficient and cost effectivemethod of bleaching hydrocarbon tackifying resins. The bleached resinsproduce adhesives free of unwanted colors when compounded with suitableelastomers without any decrease in the adhesive properties of theresulting adhesive.

FIG. 1 is a representation of the results of a color analysis of ahydrocarbon resin with a HunterLab tristimulus colorimeter according toExample II. The untreated resin is indicated by a circle, the resintreated with iodine only is indicated by an X, and the resin treatedwith an iodine supplying species and an activating hydrogen donatingspecies according to the present invention is indicated by a box.

In order to facilitate a further understanding of the invention, thefollowing examples are given for the purposes of illustrating certainmore specific details thereof.

EXAMPLE I

A reaction vessel was equipped with a stirrer, a gas inlet, additionfunnel and thermometer, and 100 parts mixed aliphatic/aromatic solventand 3 parts anhydrous aluminum chloride were added to the vessel. Whilecontinuously stirring the mixture, 100 parts of a reactive C₅hydrocarbon mixture containing cis and trans-1,3-pentadiene(piperylene), cyclopentene, 2-methyl-2-butene and lesser quantities ofC₄, C₅ and C₆ unsaturated hydrocarbons was slowly added over a fifteenminute period. The temperature of the reaction mixture was maintained at25° C. for 1.5 hours. To the reaction mixture was added 100 parts waterto decompose the active polymerization catalyst and quench the reaction.Alternatively, excess ammonia gas is sparged into the reaction mixtureuntil the catalyst is neutralized, as is shown by a loss of color. Theorganic solution was water washed and filtered to remove the decomposedcatalyst and slowly heated to 230° C. to remove unreacted monomer andsolvent. A vacuum was applied to remove the residual solvent and theresin was steam stripped to the desired softening point of about 100° C.

The resin was divided into three equal parts. Sample A was leftuntreated for comparison. Sample B was treated for 1 hour with 0.04 wt.% of an iodine supplying compound, elemental iodine, at 230° C., andthen removed from the reactor and cooled. Sample C was treated for 1hour with 0.04 wt. % of elemental iodine and 4.0 wt. % of an activatinghydrogen donating compound, limonene, at 230° C. The resin from C wasthen vacuum distilled to remove any unreacted limonene and the spenthydrogen donor (reacted limonene). The resin was removed from thereactor and cooled. Table I presents the results for the resins ofSamples A, B, and C. The resin treated with both iodine and limonene isfully three Gardner colors lighter than the untreated resin. Also, thereis no residual green tint (as seen by Tristimulus Colorimeter Analysis)as a result of the bleaching, as is seen in the resin treated withiodine alone.

                  TABLE I                                                         ______________________________________                                                                               Total                                  Sample                                                                              Final Color                                                                             Delta Color*                                                                             S.P.  Mn.** Halogen                                ______________________________________                                        A     5+        --         100° C.                                                                      1057  1,390 ppm                              B     4-        1.5        100° C.                                                                      --    1,340 ppm                                    (green tint)                                                            C     2+        3.0         97° C.                                                                       965  1,310 ppm                              ______________________________________                                         *Untreated Resin Color less Treated Resin Color                               **Number Average Molecular Weight by Vapor Phase Osmometry               

EXAMPLE II Color Analysis

Seventy-five percent solids heptane solutions of the resins from SamplesA, B, and C of Example I were analyzed with a HunterLab tristimuluscolorimeter to further characterize their visible colors. Presented inFIG. 1 is the tristimulus color comparison of the subject resins. Theiodine treated resin of B results in a reduction of the yellowness whencompared to the untreated resin of A, but no reduction in green tint.This loss of yellow intensifies the observed green tint. Theiodine/hydrogen donor treated resin of C results in a furtherincremental improvement in yellow reduction as well as halving the shadeof the green tint, thereby decreasing the observed green color.

EXAMPLE III Variation in Monomer Feed

A series of C₅ hydrocarbon resins were prepared using the polymerizationtechnique described in Example I. A reaction vessel was prepared inaccordance with Example I into which was added 100 parts mixedaliphatic/aromatic solvent, 3 parts aluminum chloride and 100 parts of amonomer feed selected from Table II. The monomer feed was added slowlyover fifteen minutes at a reaction temperature of 25° C. Upon completionof the addition, the reaction was quenched by the addition of 100 partsof water and the organic layer was separated, water washed, andfiltered. The excess solvent was removed under vacuum and the resin wassteam stripped to the desired softening point, see Table II.

                  TABLE II                                                        ______________________________________                                        Sample Resin                                                                              Monomer Feeds (wt. %)                                                                         S.P.(°C.)                                  ______________________________________                                        D           90% Piperylene and                                                                            90                                                            10% Styrene                                                       E           90% Piperylene and                                                                            92                                                            10% α-Methylstyrene                                         F           Vinyl Toluene   89                                                ______________________________________                                    

The above samples of hydrocarbon resins were heated to a molten stateand then treated with 0.04 wt. % iodine and 4.0 wt. % limonene for 1hour at 230° C. The resin was then vacuum distilled to remove anyunreacted limonene as well as spent limonene. The results for theiodine/hydrogen donor treatment are presented in Table III. There is asignificant improvement in color of at least 2 points on the Gardnercolor scale.

                  TABLE III                                                       ______________________________________                                               Gardner Color                                                          Sample Resin                                                                           Untreated resin                                                                            Treated Resin                                                                            Delta Color*                                 ______________________________________                                        D        5            2+         2.5                                          E        5            2+         2.5                                          F        7            5          2                                            ______________________________________                                         *Color of untreated resin less color of treated resin                    

EXAMPLE IV Variation in Monomer Feed

A series of mixed terpene/non-terpene hydrocarbon resins were preparedusing the technique of Example III. the monomer feed was selected fromtable IV.

                  TABLE IV                                                        ______________________________________                                        Sample Resin                                                                              Monomer Feeds (wt. %)                                                                          S.P.(°C.)                                 ______________________________________                                        G           40% Piperylene,  99                                                           40% Limonene,                                                                 20% Styrene                                                       H           60% Piperylene,  88                                                           20% Mixed C.sub.10 Terpenes,                                                  20% Styrene                                                       ______________________________________                                    

Portions of the resulting hydrocarbon resins were heated to a moltenstate and then treated with 0.04 wt. % iodine and 4.0 wt. % limonene for1 hour at 230° C. Other portions of the resins were treated only with0.04 wt. % iodine in the molten state. The results for each treatmentare presented in Table V. There is a significant improvement in colorover the starting color as well as over the color after treatment withonly iodine.

                  TABLE V                                                         ______________________________________                                        Sample                                                                              Gardner Color              Delta                                        Resin Untreated  Iodine Treated                                                                            Fully Treated                                                                           Color*                                 ______________________________________                                        G     5+         4-/3+       3-        2.5                                    H     5          4-/3+       2+        2.5                                    ______________________________________                                         *Color of untreated resin less color of fully treated resin.             

EXAMPLE V Variation in Activating Hydrogen Donating Compounds

A sample of molten resin was prepared in the same manner as Sample G ofExample IV. The Sample was carefully divided into 3 portions and theneach was treated at 230° C. for one hour with various activatinghydrogen donating compounds at 100 times molar excess with respect toiodine. The results are shown in Table VI. A sample of molten resin wasprepared in the same manner as Sample A of Example I. The resin wascarefully divided into 5 portions and then each was treated at 230° C.for one hour with various activating compounds at 100 times molar excesswith respect to iodine. The results are shown in Table VII. The resultsshow that a variety of activating compounds are available to bleachhydrocarbon tackifier resins. The use of 1,4-cyclohexadiene improves thecolor even over the use of limonene. Both compounds show distinctimprovements in color and tint with respect to using iodine alone.

                  TABLE VI                                                        ______________________________________                                                   Gardner Color    Delta                                             Activating Compound                                                                        Untreated  Treated     Color                                     ______________________________________                                        Limonene     5+         3           2.5                                       1,4-cyclohexadiene                                                                         5+         3-          3.0                                       None (Iodine only)                                                                         5+         4-(green tint)                                                                            2.0                                       ______________________________________                                    

                  TABLE VII                                                       ______________________________________                                                   Gardner Color                                                      Activating Compound                                                                        Untreated  Treated  Delta Color                                  ______________________________________                                        Limonene     5+         2        3.0                                          α-terpinene                                                                          5+         2+       3.0                                          γ-terpinene                                                                          5+         2+       3.0                                          Abietic acid 5+         3        2.5                                          None (iodine only)                                                                         5+         4-       1.5-2.0                                      ______________________________________                                    

EXAMPLE VI Hydrogen Exchange Reaction

Samples of molten resin product prepared as in Example I were treatedwith 0.05 wt. % of iodine and 10.0 wt. % of an activating hydrogen donorfor 1 hour at 230° C. The spent activating hydrogen donor was thencarefully vacuum distilled from the resin, condensed and collected. Theresin was then steam stripped to the desired softening point of 101° C.The collected distillate (which had approximately the same volume as didthe hydrogen donor which was added) was then analyzed by GLC forcomposition (See Table VIII). The distillate shows an increase in thepresence of aromatics (indicating an increase in unsaturation) whichwould be expected if the activating compound was donating hydrogen tothe resin. A comparative example was included using the aromaticpara-cymene instead of an activating compound. The use of para-cymenewith iodine results in no improvement over the use of iodine with nohydrogen donor.

                  TABLE VIII                                                      ______________________________________                                                          Before  After                                                                 Treatment                                                                             Treatment***                                        ______________________________________                                        Resin Color          5-        2+                                             (Gardner Color, Neat)                                                         Hydrogen Donor Source: Limonene                                               Dienes* (C.sub.10 H.sub.16)                                                                       99%       70%                                             Aromatics** (C.sub.10 H.sub.14)                                                                    0%       30%                                             Resin Color          5-        2+                                             (Gardner Color, Neat)                                                         Hydrogen Donor Source:                                                        Alpha-Terpinene                                                               Dienes* (C.sub.10 H.sub.16)                                                                       95%       50%                                             Aromatics** (C.sub.10 H.sub.14)                                                                    0%       50%                                             Resin Color          5-       4                                               (Gardner Color, Neat)                                                         Hydrogen Donor Source:                                                        Para-Cymene                                                                   Dienes* (C.sub.10 H.sub.16)                                                                        0%        0%                                             Aromatics** (C.sub.10 H.sub.14)                                                                   99%       99%                                             ______________________________________                                         *Predominately dipentene, terpinene, terpinene, terpinolene, phellandrene     phellandrene, isoterpinolene and other methene or menthadienes.               **ParaCymene                                                                  ***Treatment involves 0.05 wt. % iodine/10.0 wt. % Hydrogen Donor        

EXAMPLE VII Pressure Sensitive Adhesive (PSA) Formulation

Hydrocarbon resins prepared as in Example I, Samples A and C, werecompounded into the pressure sensitive adhesive formulation shown inTables IX and XI. KRATON (Shell Chemical Co.) is a styrene/butadienecopolymeric elastomer. The treated resin from Sample C resulted inequivalent tack properties while advantageously starting 2 Gardner colorunits lighter than the control resin of Sample A. the results of thetests of the tack properties of the adhesives are shown in Tables X andXII. The adhesive properties of the adhesives using the treated resinare substantially the same as those of the adhesives using the untreatedresin and the color of the adhesives with the treated resin issubstantially better than those compounded with the untreated resin.

                  TABLE IX                                                        ______________________________________                                        Component of Adhesive                                                                            Parts  % by Weight                                         ______________________________________                                        Kraton D-1107      100.0  19.90                                               Resin Tackifier    100.0  19.90                                               Antioxidant         2.0    0.40                                               Toluene            300.0  59.80                                               ______________________________________                                    

                  TABLE X                                                         ______________________________________                                        Responses Units           Untreated Treated                                   ______________________________________                                        Initial PSA                                                                             Color           3         1                                         180° Peel                                                                        Ounces/inch     55        60                                        R. T. Shear                                                                             Minutes/1"*1"*2 Kg                                                                            2,880+    2,880+                                    Loop Tack Ounces/Inch     70        70                                        S.A.F.T.  °C./Time/1"*1"*1 Kg                                                                    95/10     95/10                                     Rolling Ball                                                                            Inches          10        10                                        ______________________________________                                    

                  TABLE XI                                                        ______________________________________                                        Component of Adhesive                                                                            Parts  % by Weight                                         ______________________________________                                        Kraton D-1107      100    18.8                                                Resin Tackifier    100    18.8                                                Plastisizing Oil    30     5.6                                                Antioxidant         2.0    0.4                                                Toluene            300    56.4                                                ______________________________________                                    

                  TABLE XII                                                       ______________________________________                                        Responses Units           Untreated Treated                                   ______________________________________                                        Initial PSA                                                                             Color           3         1                                         180° Peel                                                                        Ounces/inch     40        40                                        R. T. Shear                                                                             Min/1"*1" × 2 Kg                                                                        2880+     2880+                                     Loop Tack Ounces/inch     55        45                                        S.A.F.T.  °C./Time/1"*1"*1 Kg                                                                    80/7      83/3                                      Rolling Ball                                                                            Inches          <5.0      <5.0                                      ______________________________________                                        % Solid in Adhesive: 40%                                                      Adhesive Coating Weight:                                                                           0.583 g/24 in..sup.2                                     Adhesive Coated on:  2.0 mil mylar film                                       Test Panel:          Polished Aluminum                                        ______________________________________                                    

EXAMPLE VIII Hot Melt Adhesive (HMA) Formulation

Hydrocarbon resins prepared as in Example I, Samples A and C, werecompounded into hot melt adhesive formulations shown in Table XIII.ELVAX (E. I. duPont de Nemours & Co.) is an ethylene/vinyl acetatecopolymeric elastomer. MOBILWAX 145 (Mobil Oil Co.) is a petroleum wax,PARAFLINT H-1 (Moore & Monger) is a polymethylene wax. SHELLWAX 300 is aparaffin wax. Resins prepared as in Sample G of Example IV were alsocompounded into a hot melt adhesive as is shown in Table XV. Theadhesive properties of the adhesives using the treated resins aresubstantially the same as those of the adhesives using the untreatedresins. The final colors of the adhesives with the treated resins aresubstantially better than the adhesives using the untreated resins. SeeTables XIV and XVI.

                  TABLE XIII                                                      ______________________________________                                        Component        Parts  % by Weight                                           ______________________________________                                        ELVAX 250        100    20                                                    ELVAX 210        100    20                                                    Resin Tackifier  125    25                                                    Mobil Wax 145    175    35                                                    Paraflint H-1     25     5                                                    ______________________________________                                    

                  TABLE XIV                                                       ______________________________________                                        Response  Units           Untreated Treated                                   ______________________________________                                        Initial HMA                                                                             Color           3+        2+                                        Viscosity cps             1000      1050                                      ______________________________________                                    

                  TABLE XV                                                        ______________________________________                                        Component        Parts  % by Weight                                           ______________________________________                                        ELVAX 250        100    33.3                                                  SHELLWAX 300     100    33.3                                                  Resin Tackifier  100    33.3                                                  ______________________________________                                    

                  TABLE XVI                                                       ______________________________________                                        Response  Units           Untreated Treated                                   ______________________________________                                        Initial HMA                                                                             Color           4+        2+                                        ______________________________________                                    

EXAMPLE IX Neat Resin Color Stability

One hundred grams of samples of hydrocarbon resins as prepared inSamples A and C of Example I were placed in an open container. Thecontainer was then placed in a forced air circulating oven at 130° C.The color was recorded initially once the resin became molten and thenrecorded every 24 hours for four days. See Table XVII. the treated resinshowed substantially superior thermal stability when compared to theuntreated resin.

                  TABLE XVII                                                      ______________________________________                                        Gardner Color                                                                 Time (hr.)     Untreated Treated                                              ______________________________________                                        Initial         7        3+                                                   24              9        5-                                                   48             11        5+                                                   72              12-      6+                                                   96              13+      8.5                                                  ______________________________________                                    

From the foregoing, it may be seen that the present invention provides amethod for the bleaching of dark hydrocarbon adhesive tackifying resins.This method provides an efficient and cost effective means of bleachingwhere visual appearance is important, i.e., where the adhesive is to besubstantially free of color. In addition, there is no detrimental effecton the resin as a tackifier by treatment of the resin according to thepresent invention.

Various of the features of the invention which are believed to be neware set forth in the appended claims.

What is claimed is:
 1. A formulated adhesive comprising:a tackifierresin prepared from non-terpenic C₅ to C₁₀ unsaturated monomers of amixture of non-terpenic C5 to C₁₀ unsaturated hydrocarbon monomersselected from the group consisting of piperylene, 2-methyl-2-butene,isoprene, styrene, and α-methylstyrene, the resin bleached by briningthe hydrocarbon resin to a molten state thereby producing a moltenresin, adding an iodine supplying compounds selected from the groupconsisting of elemental iodine and hydrogen iodide to the molten resin,adding an activating hydrogen donating compound selected from the groupconsisting of α-terpinene, γ-terpinene, d-limonene, 1,4-cyclohexadieneand abietic acid to the molten resin thereby forming a reaction mixture,maintaining the reaction mixture in a molten state for a period of timeof between about 15 minutes and about 120 minutes, and removing theactivating compound from the reaction mixture thereby recovering ableached hydrocarbon tackifier resin; and a copolymeric elastomer.
 2. Aformulated pressure-sensitive adhesive comprising:a tackifier resinprepared from non-terpenic C₅ to C₁₀ unsaturated monomers or a mixtureof non-terpenic C5 to C₁₀ unsaturated hydrocarbon monomers selected fromthe group consisting of piperylene, 2-methyl-2-butene, isoprene,styrene, and α-methylstyrene, the resin bleached by bringing thehydrocarbon resin to a molten state thereby producing a molten resin,adding an iodine supplying compounds selected from the group consistingof elemental iodine and hydrogen iodide to the molten resin, adding anactivating hydrogen donating compound selected from the group consistingof α-terpinene, γ-terpinene, d-limonene, 1,4- cyclohexadiene and abieticacid to the molten resin thereby forming a reaction mixture, maintainingthe reaction mixture in a molten state for a period of time of betweenabout 15 minutes and about 120 minutes, and removing the activatingcompound from the reaction mixture thereby recovering a bleachedhydrocarbon tackifier resin; and a styrene/butadiene copolymericelastomer.
 3. A formulated hot melt adhesive comprising:a tackifierresin prepared from non-terpenic C₅ to C₁₀ unsaturated monomers or amixture of non-terpenic C5 to C₁₀ unsaturated hydrocarbon monomersselected from the group consisting of piperylene, 2-methyl-2-butene,isoprene, styrene, and α-methylstyrene, the resin bleached by briningthe hydrocarbon resin to a molten state thereby producing a moltenresin, adding an iodine supplying compounds selected from the groupconsisting of elemental iodine and hydrogen iodide to the molten resin,adding an activating hydrogen donating compound selected from the groupconsisting of α-terpinene, γ-terpinene, d-limonene, 1,4-cyclohexadieneand abietic acid to the molten resin thereby forming a reaction mixture,maintaining the reaction mixture in a molten state for a period of timeof between about 15 minutes and about 120 minutes, and removing theactivating compound from the reaction mixture thereby recovering ableached hydrocarbon tackifier resin; and an ethylene/vinyl acetatecompolymeric elastomer.